Tilt and swivel mechanism for chairs



' Nov. 30, 1965 w. P. BAERMANN 3,220,688

TILT AND SWIVEL MECHANISM FOR CHAIRS Filed Aug. 21, 1965 4 Sheets-Sheet 1 INVENTOR:

WALTE R P. BAERMAHN M & M

Nov. 30, 1965 w. P. BAERMANN 3,220,688

TILT AND SWIVEL MECHANISM FOR CHAIRS Filed Aug. 21, 1963 4 Sheets-Sheet 2 I A bill/14E 0/1 INVENTOR. WALTER P. BAERMAN N M09417, 4M,M& Want A 'r'r'Ys Nov. 30, 1965 w. P. BAERMANN TILT AND SWIVEL MECHANISM FOR CHAIRS 4 Sheets-Sheet 5 Filed Aug. 21, 1963 INVENTOR: R P. BAERMANN M & Wart ATT'YS Nov. 30, 1965 w. P. BAERMANN TILT AND SWIVEL MECHANISM FOR CHAIRS 4 Sheets-Sheet 4 Filed Aug. 21, 1963 INVENTOR.

WALTER P. BAERMANN BY M07 1. W, & $02" A'rrvs United States Patent C) 3,220,688 TILT AND SWIVEL MECHANISM FOR crrams Waiter P. Baez-mama, 600 Asheville Road, Waynesvilie, N.C. Filed Aug. 21, 1963, Ser. No. 303,643 7 Claims. (6!. 248384) This invention relates to tilt and swivel mechanisms and particularly to tilt and swivel mechanisms that are used on ofiice chairs and the like.

An object of this invention is to provide a tilt and swivel mechanism, suitable for use on ofiice chairs and the like, in which the spring parts, including those which adjust spring tension, are located within the tubular base of the chair.

Another object is the provision of a tilt and swivel mechanism in which height and tension adjustments can be accomplished by merely pushing a button or twisting a lever.

A still further object is the provision of a tilt and swivel mechanism that employs the method of compression rather than elongation of the spring member.

These and other objects and advantages will become obvious when the following description is read in light of the accompanying drawings, in which:

FIGURE 1 illustrates a typical tilt and swivel mechanism, of the type herein disclosed, as it is used on an ofiice chair;

FIGURE 2 is an exploded View of one embodiment of the mechanism;

FIGURE 3 is a sectional view of the embodiment shown in FIGURE 2;

FIGURE 4 is a front elevation of the embodiment shown in FIGURE 2;

FIGURE 5 is a sectional view of a modification of the embodiment shown in FIGURE 2;

FIGURE 6 is another modification of the embodiment shown in FIGURE 2;

FIGURE 7 is a front elevation of another embodiment of the tilt and swivel mechanism;

FIGURE 8 is a section taken along line 88 of FIG- URE 7;

FIGURE 9 is a front elevation of yet another embodiment of the tilt and swivel mechanism;

FIGURE 10 is a section taken along line 10-10 of FIGURE 9;

FIGURE 11 is a front elevation of a preferred embodiment of the tilt and swivel mechanism;

FIGURE 12 is a section taken along line 1212 in FIGURE 11;

FIGURE 13 is a front elevation of another embodiment of the tilt and swivel mechanism;

FIGURE 14 is a section taken along line 14-14 in FIGURE 13; and

FIGURE 15 is a section taken along line 15-15 in FIGURE 14.

Generally described, the present tilt and swivel mechanism comprises a top plate suitable for mounting a chair seat or the like. Said top plate is tiltably mounted to a head casting which has an annular central opening. A tensioner shaft extends downwardly through said annular central opening. Said tensioner shaft is linked at its upper end to said top plate, whereby when said top plate is tilted, vertical movement is imparted to said tensioner shaft. Said head casting, with said top plate tiltably mounted thereto and with said tensioner shaft, is mounted rotatably in the tubular base of an oflice chair. A compression member, provided with means for adujsting the tension thereof and adapted to oppose the movement of said tensioner shaft is mounted within said tubular base. If it is desired, said compression member may also rotate or swivel with said head casting and said tensioner shaft. The performance of the present tilt and swivel mechanism is further improved if means are provided for adjusting the height of the top plate with respect to the tubular chair base.

In operation, the tilt and swivel mechanism functions as follows: when said top plate is tilted, the vertical movement of said tensioner shaft causes compression of said compression member, thus opposing the upward movement of the top plate and tending to restore said top plate, via said tensioner shaft, to the horizontal. Operation of the tilting mechanism is not dependent on the position of said mechanism with respect to the tubular base. The rotating function and the tilting function are independent of one another. Thus, the top plate may be tilted at the same time the head casting is being rotated within the tubular base.

Referring to the drawings in more detail, FIGURE 1 shows chair seat I mounted on top plate 2. Tilt and swivel mechanism 3 connects top plate 2 and tubular chair base 4.

In FIGURES 2, 3, and 4 one embodiment of the present invention is shown. Top plate 5 (which corresponds to plate 2 in FIGURE 1) has corner holes 6 whereby top plate 5 can be attached to a chair seat, as shown in FIG- URE 1. Top plate 5 has central hole 7 through which push ball 8 is attached by nut 9. Push block 10 is forcefitted over push ball 8, and is made of material hard enough to withstand the forces demanded of it, yet resilient enough to be force-fitted over push ball 8. Head casting 11 is attached to top plate 5 by means of pivot arms 12, pivot pin 13, bushings 14, pivot tabs 15 and pin 16.

Top plate 5 is shown in the extreme upward position which is maintained by notches 17 in pivot tabs 15 acting against pivot arms 12. Downward movement of top plate 5 moving about pivot pin 13 causes push ball 8 and push block 10 to move downward against head 18 of tensioner shaft 19 extending through central opening 20 in head casting 11. Lower portion 21 of head casting 11 is threaded as is upper collar 22 of spring housing 23. Compression washer 24 is welded or permanently attached to tensioner shaft 19, and moves with tensioner shaft 19. Tensioner shaft 19, which resembles in form an automobile exhaust valve, is thick and round at head 18 and has a square shaft 25. Compression washer 24 acts against spring retainer washer 26, which in turn acts against spring 27. Ratchet housing retaining washer 28, together with lower end 21 of head casting 11, forms the upper limit for movement of spring retainer washer 26 and tensioner shaft 19.

Tensioner shaft 19 passes through tensioner screw 29, which has either a square, splined, or a key-wayed hole in the center which allows upward or downward movement of shaft 25. Tensioner screw 29 is threaded on the outside to receive spring tensioner nut 30, which holds spring 27 within housing 23 by means of tensioner washer 31. Upward movement of tensioner shaft 19 is limited by retainer nut 32 which is held in position by pin 33. Lower end of screw 29 rests against bumper washer 34, while nut 32 turns against bumper washer 35. Downward movement of tensioner shaft 19 is limited by tensioner shaft head 18 abutting against bumper washer 36.

The sequence of the tilting operation then is as follows: top plate 5 pivots about pivot pin 13 pushing push ball 8 downward, Push ball 8 pushes against push block 10, which pushes against tensioner shaft 19 at its head 18. Compression washer 24 attached to tensioner shaft 19 pushes against spring retainer washer 26, compressing the spring 27 held against tensioner washer 31.

Ratchet drive housing 37 drives ratchet pawl 38. Ratchet pawl 38 in turn drives ratchet housing 39. Ratchet housing 39 has a central opening corresponding in shape to push rod shaft 25 whereby ratchet housing 39 turns with tensioner shaft 19 about its perpendicular axis. Tensioner washer 31 and tensioner nut 30 are friction-held by spring 27. Hence, tensioner screw 29 can rotate without rotating nut 30.

The sequence of spring tension adjustment, then is as follows: ratchet drive housing 37 drives ratchet pawl 38, which in turn drives ratchet housing 39. Ratchet housing 39 rotates tensioner shaft 19, which rotates in turn tensioner screw 29. Tensioner nut 39 held motionless by spring 27 acting against tensioner washer 31, moves up or down tensioner screw 29 as it is rotated, thus, varying the tension of spring 27.

Spring housing collar 22 rotates with respect to tubular chair base 40 on annular bearing 41. Snap ring 43 prevents the entire tilt and swivel mechanism from being lifted out of tubular chair base 40.

FIGURE shows a modification of the embodiment of the tilt and swivel mechanism shown in FIGURES 2, 3, and 4. Instead of the coil spring 27 used in FIGURES 2, 3, and 4, conical disc spring 44 is used in FIGURE 5. Downward motion of tensioner shaft 45 results in compression of springs 44 between compression washer 46 and tensioner washer 47. FIGURE 5 also illustrates a slight modification in the arrangement of the tension adjustment parts. Tensioner screw 48 extends downwardly through spring housing 49. Tensioner nut 50 is a clinch nut which has a collar extension 50a. Collar 50a passes through spring housing 49 and is clinched or staked over to provide a permanent bond. Tensioner shaft 45, in FIGURE 5, is round. Shaft 45 must be key-wayed or splined so that shaft 45 rotates with screw 48.

FIGURE 6 illustrates another form of compression device that can be used in conjunction with the instant tilt and swivel mechanism. Head casting 51, tubular chair base 52 and tensioner shaft 53 are all of standard design. Attached to shaft 53 is compression washer 54. Head casting 51 has threaded rim 55. Tensioner housing 56 has threaded upper collar 57 which screws onto head casting 51 at threaded inner rim 55. Compression component 58, mounted inside tensioner housing 56, utilizes the elastic properties of stressed rubber. The rubber component 59 is contained within a metal sleeve 60 and vulcanized thereto. Rubber component 59 is also vulcanized to a central sleeve 61, through which passes tensioner shaft 53. Alternatively, rubber component 59 may be vulcanized directly to tensioner shaft 53. If it is desired, rubber component 59 may be cemented to outer sleeve 60 and inner sleeve 61 of tensioner shaft 53, rather than being vulcanized thereto.

FIGURES 7 and 8 show yet another embodiment of the present tilt and swivel mechanism. As shown in the drawings, head casting 62, which also serves as a spring housing, is attached to projecting tabs 63 of top plate 64 by means of pivot pin 65. In use, top plate 64 hinges or tilts about an axis passing through pivot pin 65. Head casting 62 contains a spring 66, comprising a series of conical spring washers or other type of compression spring,

mounted concentrically about a tensioner shaft 67, which is attached indirectly to top plate 64 by means of tensioner shaft end 68 and pivot tabs 69. Tensioner shaft end 68 is screwed onto the upper threaded end of tensioner shaft 67 and is cross-pinned to pivot tabs 69, which are in turn staked or welded to the top plate 64. Spring base plate 70 is welded to tensioner shaft 67, thus, compressing the spring 66 against the restraining concentric shoulder in head casting 62. The entire sub-assembly of top plate 64, head casting 62, spring 66 and tensioner shaft 67 is seated in mounting tube 71 and allowed to rotate freely within this tube with the assistance of bushing 72 and 4. bumper washer 73. This provides for overall rotation of the top plate 64, and the chair seat which is pivotally attached thereto. In use, tilting of the top plate 64 exerts an upward pulling force on spring base plate 76 via tensioner shaft 67, thus compressing the spring 66.

The tab 74 of lock lever 75 passes through a small opening in the wall of mounting tube 71, when the lever 75 is depressed against lever spring 76. The lever lock 75 is pivotally attached to mounting tube 71 by means of a hinge pin 77 passing through the lever lock 75 and a pin tab 78 which has been welded to mounting tube 71. \Vhen lever lock 75 is held in the depressed state and the top plate 64 is rotated, the projecting tab 74 of the lever lock 75 enters the mounting tube 71 to the extent that it engages the downward formed flanges 79 of the spring base plate 70. This prevents rotation of spring 66 and tensioner shaft 67, causing tensioner shaft 67 to run either up or down the threads in tensioner shaft end 68 determining the initial tilt tension on spring 66. Height adjustment shaft 80 prevents screw out of tensioner shaft 67.

Lever lock 75 also serves to hold head casting 62 within mounting tube 71. A projection 81 on the upper end of lever lock 75 rides within an annular groove 82 in head casting 62. This method of attachment simplifies assembly or required maintenance.

Height adjustment shaft 80 is fixed to mounting tube 71 by brazing, force-fitting or other suitable means, and extends downward into the tubular chair base 83. Metal bushing 84 and metal sleeve 85 keep the shaft concentrically alinged Within tubular chair base 83. A height adjustment ring 86 contains an adjustment nut 87 which engages threads on the height adjustment shaft 80. Thus, when height adjustment ring 86 is rotated by hand, the height adjustment shaft 80 begins to move upward or downward within tubular chair base 83. Lock screw 88 prevents possible lift-out of the entire height adjustment assembly.

FIGURES 9 and 10 illustrate a still further embodiment of the instant tilt and swivel mechanism. As with the form of the invention shown in FIGURES 7 and 8, the embodiment shown in FIGURES 9 and 10 provides both a mechanism for adjustment of spring tension and a mechanism for adjustment of height.

Top casting 9:) is attached to top plate 89 by means of pivot tabs 91 and pivot pin 92. Top plate 89 tilts by the upward rotation of a center point which. is located in tensioner shaft end 93. The top plate 89 is shown in an extreme downmost position which is maintained by the bottom flange of tensioner shaft end 93 abutting against the limit of depression in top casting 90. Upper movement of top plate 89 is checked by the notch configuration that exists between pivot tabs 91 and cooperating connection 94 in top casting 9t). Tensioner shaft end 93 is attached via pin 95 to pivot tabs 96, which are in turn welded to top plate 89. Tensioner shaft 97 is threaded into tensioner shaft end 93, and extends downwardly through the annular central opening in top casting 99. Tensioner shaft 97 extends downwardly through spring 98, which is a conical disc spring or other type of compression device. The upper end of spring 98 is seated against top casting 90. The lower end of the spring 98 is held against spring retainer 99. Tensioner casting 169, threaded and attached at the lower end of tensioner shaft 97, moves with tensioner shaft 97 and against spring retainer 99.

The sequence of spring compression is, then, as follows: top plate 89 tilts where the upward rotation of a center point located in tensioner shaft end 93 about an axis or pivot point located in pivot pin 92. Upward movement of top plate 89 results in upward movement of tensioner shaft 97 via pivot tabs 96 and tensioner shaft end 93. Spring tensioner casting moves upward with tensioner shaft 97 forcing spring retainer 99 upward, compressing spring 98.

Spring tensioner casting 100 moves up and down on the threaded part of tensioner shaft 97 between upper limiting nut 101 and lower limiting nut 102. When tensioner casting 100 is nearest upper limit nut 101, strongest tension is accomplished and vice versa as it approaches lower limiting nut 102. A protrusion 103 on tensioner casting 100 extends downwardly and rotates close to the wall of tubular chair base 104. The bottom push button 105 in lower casting 106, opposite slot 107 in tubular chair base 104, is the tension adjustment push button. When tension adjustment button 105 is depressed, it moves through slot 107 in tubular chair base 104 into the path of rotating tensioner casting protrusion 103. This stops the rotation tensioner casting 100, forcing it to move upward or downward along the threads of tensioner shaft 97.

The sequence of tension adjustment then is as follows: top plate 89 is rotated via the chair to which it is attached. At the same time, tension adjustment button 105 is depressed, moving it through slot 107 and tubular base 104 and into the path of the protrusion 103 of tensioner casting 100. This forces tensioner casting up or down against the spring, thus varying tension.

Top casting 90 and jack screw housing 108, because of multiple friction forces, swivel together upon swivel bearing 109. Jack screw housing 108 is held with the remainder of the unit to tubular chair base 104 at snap ring 110, which also acts as a bumper for quiet operation. Bottom casting 106 is permanently attached to tubular chair base 104, and contains two push buttons 105 and 111. The top button 111 is the height adjustment button. When it is depressed, it falls into a slot 112 located in the bottom of jack screw housing 108. When the housing 108 is rotated, thus bringing the slot 112 opposite button 111, button 111 falls into the slot 112. This stops the rotation of the jack screw housing 108. Top casting 90 continues to rotate and rides up the threads on jack screw housing 108 until the proper height is achieved.

The sequence of height adjustment, then, is as follows: top plate 89 is rotated via its attached chair, which in turn rotates top casting 90 and jack screw housing 108. While rotation is taking place, height adjustment push button 111 is depressed, falling into slot 112 at the bottom of jack screw housing 108. This stops housing 108 from rotating, but does not stop top casting 90. Top casting then moves up threads in the jack screw housing.

FIGURES 11 and 12 show a preferred embodiment of the instant invention. Top plate 113 is attached to head casting 114 by means of pivot tabs 115, pivot pin 116 and bushings 116a. Tensioner shaft 117 with head 118 extends downwardly through the annular central opening in head casting 114. Within head casting 114 is a metal sleeve 119 with upper flange 120. Vulcanized to or cemented to metal sleeve 119 is rubber spring component 121. Spring unit 121 is vulcanized to or cemented to tensioner shaft 117. Spring retainer washers 122 are welded to tensioner shaft 117 at each end of spring unit 121.

Push ball tension adjustment handle 123 is attached to top plate 113 by tension adjustment screw 124. Screw 124 is held to top plate 113 by bushing 125. Push ball tension adjustment handle 123 is connected to head 118 of tensioner shaft 117 by push block 126. The push block 126 is made of material hard enough to withstand forces demanded of it and yet with enough resilience to be force-fitted over the push ball tension adjustment handle 123. Push block 126 pushes and slides slightly against head 118 of tensioner shaft 117.

The sequence of tilting is as follows: pivoting top plate 113 about an axis or pivot point lying within pivot point 116 causes push ball tension adjustment handle 123 and push block 126 to push against head 118 of tensioner shaft 117, compressing rubber spring unit 121.

Push ball tension adjustment handle 123 swings through a 200 arc with a total up and down adjustment space of A; of an inch along the threads of tension adjustment screw 124. The handle 123 is merely moved until the desired tension is obtained. Alternatively, instead of the handle 127, a knob (not shown) may be provided.

FIGURES 13, 14, and 15 show yet another embodiment of the present invention. Base plate 128 is fastened to head casting 129 by means of pivot tabs 130, pivot bolt 131, pivot nut 132 and noiseless bearings 133. Head casting 129, is secured to tubular chair base 134 by an expansion ring 1 35. As top plate 128 is rotated the head casting 129 turns between bearing surfaces 136 and 137. Tensioner shaft 138 is pinned to pivot tabs 139 by pin 140. Base shaft collar 141 fits on top of tubular chair base 134. Seated against base shaft collar 141 are conical disc springs 142. The conical disc springs 142 are retained at the bottom by a plate 143, which moves vertically on two runners 144 which prevent the plate 143 from turning within the tubular chair base 134. Plate 143 is threaded onto tension adjusting shaft 145. At the bottom end of tension adjusting shaft 145 is a stop 146 and a bearing surface 147. Stop 146 is bolted to tensioner shaft 138.

As the top plate 128 is tilted, it rotates about pivot bolt 131 thus raising the tensioner shaft 138 thus raising tension adjusting shaft 145, which in turn compresses spring 142.

For the adjustment of the spring tension one engages lift-up key 148, which pivots on a pin 149, into one of four slots 150 which radiate from the center of tension adjusting shaft collar 152. By rotating the top plate 128, tension on the springs 142 may be increased or decreased, since tension adjusting shaft 145 now rotates with respect to non-rotatable plate 144 and bolt 151, which thus move up or down along tension adjusting shaft 145. While adjustment is being accomplished, head casting 129 and tension adjusting shaft collar 152 as a unit rotate on bearing surface 136. When lift-up key 148 is returned to its normal vertical position, tension is no longer adjusted by rotating the to plate 128.

The invention is hereby claimed as follows:

1. A resiliently-biased tilt mechanism comprising a vertical, hollow, mounting post, including a head on the upper end of said post, a substantially horizontal, tiltable member pivotally supported on said head with the pivot axis thereof being substantially horizontal and laterally displaced with respect to the longitudinal axis of said post, a resiliently deformable member in said post, means holding one part of said deformable member against axial displacement in said post, and means coacting between another part of said deformable member and said tiltable member at a position on the latter directly above said post to deform resiliently said deformable member when said tiltable member is tilted about said pivot axis in a direction away from the substantially horizontal position, and bias-adjustment means for adjusting, in response to rotation of said tiltable member, the resilient bias of said deformable member against said tilting of said tiltable member.

2. A mechanism as claimed in claim 1 wherein said deformable member is resiliently deformable in longitudinal compression.

3. A tilt mechanism as claimed in claim 1, a vertical shaft movable longitudinally in said post, means connecting the upper end of said shaft with said tiltable member, and means connecting the lower portion of said shaft and said another part of said deformable member and providing the connection between shaft and said deformable member to cause said deformable member to deform resiliently when said tiltable member is tilted.

4. A tilt mechanism as claimed in claim 3 wherein said deformable member is a longitudinally compressible coil spring.

5. A tilt mechanism as claimed in claim 3 wherein said deformable member is a series of conical disc springs.

6. A tilt mechanism as claimed in claim 3 wherein said deformable member is an elastomer tube surrounding said shaft.

7. A tilt mechanism as claimed in claim 1, means on said post supporting said head, said tiltable member and said deformable member for swivel movement as a unit on said post, and manually operable means movable from an inactive position permitting said swivel movement without said biasadjustment to an active position, in

References Cited by the Examiner UNITED STATES PATENTS Trapp 248406 Schaifner 297-205 Bethke 248-402 Herold 248-375 Stewart 2671 Clay 2671 which said bias-adjustment means is activated by rotation 10 CLAUDE A. LE ROY, Primary Examiner.

of said tiltable member. 

1. A RESILIENTLY-BIASED TILT MECHANISM COMPRISING A VERTICAL, HOLLOW, MOUNTING POST, INCLUDING A HEAD ON THE UPPER END OF SAID POST, A SUBSTANTIALLY HORIZONTAL, TILTLABLE MEMBER PIVOTALLY SUPPORTED ON SAID HEAD WITH THE PIVOT AXIS THEREOF BEING SUBSTANTIALLY HORIZONTAL AND LATERALLY DISPLACED WITH RESPECT TO THE LONGITUDINAL AXIS OF SAID POST, A RESILIENTLY DEFORMABLE MEMBER IN SAID POST, MEANS HOLDING ONE PART OF SAID DEFORMABLE MEMBER AGAINST AXIAL DISPLACEMENT IN SAID POST, AND MEANS COACTING BETWEEN ANOTHER PART OF SAID DEFORMABLE MEMBER AND SAID TILTABLE MEMBER AT A POSITION ON THE LATTER DIRECTLY ABOVE SAID POST TO DEFORM RESILIENTLY SAID DEFORMABLE MEMBER WHEN SAID TILTABLE MEMBER IS TILTED ABOUT SAID PIVOT AXIS IN A DIRECTION AWAY FROM THE SUBSTANTIALLY HORIZONTAL POSITION, AND BIAS-ADJUSTMENT MEANS FOR ADJUSTING IN RESPONSE TO ROTATION OF SAID TILTABLE MEMBER, THE RESILIENT BIAS OF SAID DEFORMABLE MEMBER AGAINST SAID TILTING OF SAID TILTABLE MEMBER. 